<!DOCTYPE html
     PUBLIC "-//W3C//DTD XTHML 1.0 Strict//EN"
     "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
  <head>
    <link rel="stylesheet" type="text/css" href="styles.css" />
    <title>uthash: a hash table for C structures</title>
  </head>
  <body>

  <div id="banner">
  <img src="banner.png" alt="uthash: a hash table for C structures" />
  </div> <!-- banner -->

  <div id="topnav">
  <a href="https://github.com/troydhanson/uthash">GitHub page</a> &gt;
  uthash home <!-- https://troydhanson.github.io/uthash/ -->

<a href="https://twitter.com/share" class="twitter-share-button" data-via="troydhanson">Tweet</a>
<script>!function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs");</script>
  </div>

  <hr />
  <div id="mid">

      <div id="nav">

        <h2>documentation</h2>
        <div><a href="userguide.html">uthash</a></div>
        <div><a href="utlist.html">utlist</a></div>
        <div><a href="utarray.html">utarray</a></div>
        <div><a href="utringbuffer.html">utringbuffer</a></div>
        <div><a href="utstack.html">utstack</a></div>
        <div><a href="utstring.html">utstring</a></div>

        <h2>download</h2>
        <h3>GNU/Linux, Windows</h3>
        <div><a href=https://github.com/troydhanson/uthash/archive/master.zip>uthash-master.zip</a></div>
        <div><a href=https://github.com/troydhanson/uthash>git clone</a></div>

        <h2>license</h2>
        <div><a href="license.html">BSD revised</a></div>


        <h2>developer</h2>
        <div><a href="https://troydhanson.github.io/">Troy D. Hanson</a></div>

        <h2>maintainer</h2>
        <div><a href="https://github.com/Quuxplusone">Arthur O'Dwyer</a></div>


      </div>

      <div id="main">
        Any C structure can be stored in a hash table using uthash. Just add a
        <em>UT_hash_handle</em> to the structure and choose one or more fields
        in your structure to act as the key. Then use these macros to store,
        retrieve or delete items from the hash table.

<div class="listing">
Example 1. Adding an item to a hash.
<div class="code">
<pre>
#include "uthash.h"

struct my_struct {
    int id;            /* we'll use this field as the key */
    char name[10];
    UT_hash_handle hh; /* makes this structure hashable */
};

struct my_struct *users = NULL;

void add_user(struct my_struct *s) {
    HASH_ADD_INT(users, id, s);
}

</pre>
</div> <!-- code -->
</div> <!-- listing -->

<div class="listing">
Example 2. Looking up an item in a hash.
<div class="code">
<pre>
struct my_struct *find_user(int user_id) {
    struct my_struct *s;

    HASH_FIND_INT(users, &amp;user_id, s);
    return s;
}

</pre>
</div> <!-- code -->
</div> <!-- listing -->

<div class="listing">
Example 3. Deleting an item from a hash.
<div class="code">

<pre>
void delete_user(struct my_struct *user) {
    HASH_DEL(users, user);
}

</pre>
</div> <!-- code -->
</div> <!-- listing -->

 For more information and examples, please see the <a href="userguide.html">User Guide.</a>

</div> <!-- main -->
</div> <!-- mid -->

   <hr />
  <div id="footer">
  </div> <!-- footer -->

  </body>

</html>

